This invention relates generally to agricultural air carts and, more specifically, to apparatus for selectively controlling the operation of the air cart metering system.
As the size of agricultural implements continues to grow, the versatility of such implements becomes more significant. Large seeding implements serve to aid the farmer in efficiently seeding his fields in less time. However, a significant problem arises from this situation. Farmland is not sized in proportion to the implement size thereby creating a dilemma for the operator when only half the implement width is remaining as a final seeding pass. It simply is not acceptable for the operator to double seed a pass of half the width of the implement in order to seed the last remaining section of land. In doing so, seeds are wasted and consistent crop yield is sacrificed. In the alternative, it is also not acceptable for the last pass not to be seeded at all. Unused land is wasted crop production land.
Metering systems commonly have means to isolate a selected meter box from operation. Therefore, the ground openers associated with the particular meter that has been shut off do not receive seed. This allows the operator to traverse land with the implement without utilizing the entire implement width for seeding. In U.S. Pat. No. 5,078,066 a wrap spring clutch allows for disengagement of individual meter rollers from the rotational actuation of the common shaft on which they are mounted. The operator can selectively disengage meter rollers from rotation either automatically (electrically) or mechanically. U.S. Pat. No. 5,024,173 discloses a dispenser that utilizes a spring to bias a clutch assembly to engage with a metering roller. A control knob and cam are used to move the clutch assembly away from the metering roller(s) in order to disengage them. Various other means of disengaging separate meter rollers from their drives are disclosed in U.S. Pat. Nos. 5,632,212, 3,982,670 and U.S. Pat. No. 4,508,243. In all this prior art, means are provided to shut off the rotation of whole meter rollers in systems where multiple meter rollers are provided. However, they do not provide means to selectively shut off or disable a portion, e.g. one-half of a metering roller located in a common housing.
Canadian Patent 1,149,235 discloses a means to disengage one or-more meter rollers within a common housing. However, this system is manually operated and the operator must stop the implement and exit his tractor cab. In addition, much of the prior art also relies on a multitude of mechanical parts giving way to significant maintenance problems and expenses.
Other implements offering the ability to isolate a meter box from operation are the Morris 7000 Series air seeder and John Deere 1900 Commodity air cart.